Science is a communal activity which is best advanced with collaborations both intellectual and experimental. The overlapping research interests and collaborations of laboratories in the program is strongly reinforced by sharing of several essential core facilities. All investigators in this grant have offices and laboratories in contiguous space on the 5th floor of the Center for Cancer Research. To both promote interactions between scientists in the lab and to more cost-effectively use large equipment, the four groups share several common facilities. These include: -200 degrees cell line storage devices (some liquid nitrogen cooled), -70 degrees freezers, ultracentrifuges and rotors, intermediate speed centrifuges (Sorvall), gel dryers and vacuum pumps, bacterial fermentation facilities, spectrophotometer, phosphorimager, dark room with automatic developer, photographic device for gels, scintillation counter and computers. This equipment is located in three communal rooms which are accessible from public halls. The four groups share the work of a lab aide who is responsible for handling glassware. The four groups also share a common dry ice chest which is located with direct access from the hall. The sharing of these common facilities/equipment is important for building a feeling of shared responsibility, goals and ideas among the four laboratories. It also increases the intensity of use which reduces costs. Finally, as students and fellows compete for use of this equipment, they exchange ideas and begin collaborations. The sharing of common equipment breaks down the isolation of the four groups.